Installation of switchgear assemblies, such as gas-insulated switchgear assemblies, at least partially underground is known, for example, from DE 4210901A1. The switchgear assembly designed as a compact station according to DE 4210901A1 is integrated in a reinforced-concrete chamber which is partially recessed in the earth and has corresponding ventilation options on the upper face of the chamber for connection between the interior of the chamber and the atmosphere.
DE 2915504A1 discloses a chamber with a cast foundation for an accessible electrical power supply station which is at risk of explosion and has a transformer and a switchgear assembly which is protected against interference arcs and is arranged on a false floor. A ventilation duct which is routed beneath the transformer and is connected to the external air via an air shaft is provided between the false floor and the foundation. An expansion space is also provided between the false floor and the foundation, that is to say above and below the switchgear assembly. The boundary walls of the expansion space have pressure-relief openings and are connected to the ventilation duct and/or an exhaust-air opening in the roof or in the upper part of a side wall of the chamber.
DE 298 04 893 U1 discloses a transformer station for medium and low voltages, a transformer and also a medium- and a low-voltage component being arranged in the housing of the transformer station. The transformer station also has a transportation opening in the roof of the housing. The transportation opening facilitates installation of the devices of the transformer station and maintenance of the devices.
In order to make access and transportation as well as servicing of the power transformers of transformer stations convenient, the power transformers are usually arranged at ground level.
If, however, the power transformers are arranged underground, a dedicated access point is usually provided for each transformer. The access point does not have a structure built over it, in order to allow permanent access to the transformer. Furthermore, separate devices for ventilation and climate control are provided to ensure the functionality of the switchgear assembly or transformer stations.
In the case of the transformers being arranged by being partially or completely recessed in the earth, they may also be covered only by protective grids or similar devices in order to, on the one hand, provide a mechanical protective function, but, on the other hand, to allow air flow for cooling purposes.
The above-described known designs of a switchgear assembly or transformer stations relate essentially to compact stations but not to larger transformer stations. Furthermore, the described concepts do not provide the option of a structure being built over the entire station since access to the power transformer is to be ensured and the space required above-ground by the switchgear assemblies or transformer stations is very large owing to the dedicated access points to the respective power transformer. In addition, a large enough space requirement has to be provided for the requisite ventilation shafts.
An objective of the underground station of the present disclosure is to minimize the openings and the above-ground space requirement. Furthermore, it should be possible to build a structure over the station and also to integrate the station in public spaces.
Considerable safety risks to the environment arise if transformers are merely recessed in the earth. The present disclosure largely avoids safety risks to, for example, adjacent public spaces owing to being structurally separate. It additionally permits complete visual integration into an urban environment and minimizes the influence of the assembly on the environment.